In this paper, the modelling of an autonomous variable speed micro hydropower station is presented. It is composed of a doubly fed induction generator linked mechanically and electrically to a permanent magnet synchronous machine which may recover or supply the slip power and which feeds the...

In the future power system based on active distribution grid, allowing some portion to be disconnected, the concept of universal wind turbine systems may arise. This concept covers both grid-connected and island operations. This may happen if the voltage goes outside the range recommended by the...